Polyurethane Injection Resin Stabilizes Bridge

Situation: The province of Saskatchewan in central Canada has an enormous inventory of roads and bridges. In fact, its 190,000 kilometers of roadway are the most of any province or territory in Canada. The many rivers and streams crisscrossing the province mean that there is also an enormous inventory of bridges, many of which are experiencing the adverse effects of time and climate.

The successful project was profiled in a September 2014 issue of Heavy Equipment Guide:

“In this case, [New Shield president Larry] Graham worked with the Ministry and Martech to design a mitigation technique that would fill voids and stabilize loose soil with minimal expansion, and used a hydrophobic formulation that would not degrade when exposed to water – in fact, moisture in the surrounding soil is required for the resin to set… The idea is to fill voids in such a way that subsequent inflows and leaks are diverted and prevented in ways that eliminate any future erosion.”

The genius part of the project was the decision to inject the grout from underneath the bridge, allowing the roadway to remain open throughout the project. The hard cost of the project was comparable to a traditional replacement project, “but there was a big advantage to the public – user costs don’t show up on our bottom line, but avoiding traffic closures would save a lot of time and inconvenience for the people we serve,” said ministry bridge preservation engineer Brodie Thompson, P.Eng to the magazine.

As road authorities across North America face a major problem with crumbling road and bridge infrastructure, injection resins offer a much faster and less disruptive option for repair and renewal.